[chromium] build xdisplaycheck when building DRT
https://bugs.webkit.org/show_bug.cgi?id=112636

Reviewed by Tony Chang.

It appears that we need xdisplaycheck to be built in order for
Xvfb to be started correctly on the bots, and DRT was missing
a dependency on it. This may be the cause of the ASAN bot not
starting up properly (it only builds DRT).

* DumpRenderTree/DumpRenderTree.gyp/DumpRenderTree.gyp:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@146148 268f45cc-cd09-0410-ab3c-d52691b4dbfc